The present invention relates to the treatment of Lewis base containing polymers to improve the antistatic, hygroscopic and dye receptive properties of the polymer structure. More particularly, the invention is directed to the modification of Lewis base polymers by means of an aqueous treating solution to form branched polymers with improved properties while retaining the essential structural shape of the polymer.
It has been known in the prior art to graft-polymerize water-soluble polymers such as acrylic acid, acrylamide and N,N'-methylene-bis-acrylamide onto fibers to impart antistatic and water absorption properties to the fibers. However, such graft polymerization processes have been problematical due to difficulties in controlling the process conditions and the tendency to form large amounts of homopolymers which must be removed from the final product as well as the process equipment. Some of these processes and the difficulties therewith are discussed in more detail at column 1 of U.S. Pat. No. 4,135,877.
One patent which is representative of the prior art is U.S. Pat. No. 3,313,591 issued to David Tanner of E. I. duPont de Nemours and Company, which describes a process of graft polymerizing ethylenically unsaturated monomers to polycarbonamides to improve various properties of the polymer structure. According to that process, polymerization initiators were eliminated and heat was used as the sole graft initiator for producing the free radicals necessary for graft polymerization.
A more recent attempt to cure the deficiencies of the prior art is disclosed in U.S. Pat. No. 4,135,877 issued to Akira Aikawa et al. of Kanebo, Ltd. which discloses a process of graft polymerizing certain selected vinyl monomers to polyamide fibers or fibrous structures. According to the process described in that patent, polymerization initiators are eliminated and heat is used as in the Tanner method, but the aqueous treating solution also contains an acid.
Other patents disclosing the graft polymerization of monomers to polyamides and other polymer structures include U.S. Pat. Nos. 3,097,185; 3,099,631; 3,252,880 and 3,278,639. However, the methods of these patents involve the use of ionizing radiation or the formation of a polymer melt in order to effect the graft polymerization.
While many of these processes of the prior art result in improved antistatic, hygroscopic and dye receptive properties in the trunk polymer, they have not been entirely successful commercially due to the difficulties due to the simultaneous formation of homopolymers which are difficult to remove from the final product and the process equipment. Yet, the improvement of such properties of polymer fabrics is important since the characteristic static cling, poor water absorbency and poor dye receptivity of, for example, polyamides have limited the commercial acceptance of nylon fabrics.